TALANTA
·
2017
·
IF 4.162
Yan Xiong,Jiayi Wu,Qing Wang,Jing Xu,Shenwen Fang,Jie Chen,Ming Duan
In this work, a miniaturized optical sensor was developed for fluoride determination in tea samples to evaluate their specific risks of fluorosis for public health based on evanescent-wave interaction. The sensor design was integrated on the optical fiber by utilizing the evanescent wave produced on the fiber surface to react with sensing reagents. According to the absorption change at 575 nm, fluoride could be determined by colorimetric method and evaluated by Beer's law. With improved performances of small detection volume (1.2 μL), fast analysis (0.41 min), wide linear range (0.01–1.4 mg L −1 ), low detection limit (3.5 μg L −1 , 3σ) and excellent repeatability (2.34%), the sensor has been applied to fluoride determination in six different tea samples. Conventional spectrophotometry and ion chromatography were employed to validate the sensor's accuracy and potential application. Furthermore, this sensor fabrication provided a miniaturized colorimetric detection platform for other hazardous species monitoring based on evanescent wave interaction.
研究领域:
分析化学
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环境科学
·
公共健康
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Soft Matter
·
2018
·Vol. 14
·期 36
·7516-7525
·
IF 3.709
Ming Duan,Jiayi Wu,Yan Xiong,Shenwen Fang,Jie Chen
Different molecular structures lead to different adsorption performances. In this work, the adsorption behavior of two organic dyes, namely, crystal violet (CV, triphenylmethane dye of symmetric structure) and methylene blue (MB, azo dye of linear structure), were investigated, characterized and differentiated at the silica/water interface using the total internal reflection induced near field evanescent wave (TIR-NFEW) platform. According to the change in the evanescent wave intensity and following Beer's law, the adsorption behaviors of CV and MB can be monitored real time and sensitively. On one hand, the Langmuir adsorption model was applied to obtain the related thermodynamic data (including adsorption equilibrium constant (Kads) and adsorption free energy (ΔG)). With ΔG(MB) = −25.7 ± 1.7 kJ mol−1 < ΔG(CV) = −21.5 ± 0.6 kJ mol−1 < 0, the linear MB showed a higher spontaneous adsorption ability than the symmetric CV at the silica/water interface. On the other hand, a two-step adsorption kinetic model was applied to obtain the dynamics data including the linear adsorption rate constant (k1) and the exponential adsorption rate constant (k2). With k1(CV) < k1(MB) and k2(CV) ≈ k2(MB), MB diffused faster than CV at the first diffusion step but had nearly the same interaction speed as CV in the second adsorption step. A molecular-aligned-mechanism was successfully proposed to describe the interfacial interaction process for both CV and MB that includes molecular reactions involving electrostatic attraction of type I SiO− and H-bonds of type II SiOH. This work provides new insights into the molecular-level interpretation of the adsorption of the azo and triphenylmethane dyes at the silica–water interface.
研究领域:
物理化学
·
界面科学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2021
·
IF 4.126
Sha Qin,Yan Xiong,Jun Li,Haiqin Wan,Shenwen Fang,Ming Duan,Rui Li,Donghua Liao
In this work, the adsorption and photodegradation performance of dye pollutant methylene blue (MB) on the g-C3N4 surface was real-time investigated based on attenuated total reflectance induced evanescent spectroscopy (ATR-ES). By coating g-C3N4 on a silica optical fiber (SOF) surface coupled to LED, the produced ATR-ES was interacted with MB adsorbed on the g-C3N4 interface. Therefore, the measurement processes were in situ monitored and real-time evaluated according to ATR-ES change. For adsorption investigation with a red-LED, the change of “red” ATR-ES indicated the adsorption process was spontaneous. At the first stage, the fast adsorption was mainly due to electronic attraction. At the second stage, the slow adsorption was mainly due to the π–π interaction. For photodegradation investigation with a UV-LED, the change of “violet” ATR-ES indicated MB was oxidized by a hydroxyl radical (•OH) and superoxide radical (•O2–) to upset adsorption–desorption equilibrium. The surface apparent adsorption rate was 16 times as high as the apparent photodegradation rate constant, which indicated that the photodegradation process was the main rate control step of photocatalytic degradation reaction. The performances were characterized and verified by SEM measurements, zeta potential analysis, XRD analysis, FTIR investigation, and fluorescence imaging. By utilizing ATR-ES properties on the SOF surface, the adsorption-degradation interaction was continuously real-time monitored.
研究领域:
环境科学
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材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2018
·Vol. 20
·期 28
·19208-19220
·
IF 3.906
Yan Xiong,Jie Chen,Ming Duan,Shenwen Fang
The interfacial adsorption and interaction of crystal violet (CV) at the silica–water interface was real-time measured based on a total-internal-reflection-induced near-field evanescent wave (TIR-NFEW). A silica optical fiber (SOF) was employed as a charged substrate for CV adsorption and as a light transmission waveguide for evanescent wave production for the investigation system. According to the change of evanescent wave intensity, the CV adsorption behavior could be real-time monitored at the silica–aqueous interface. The Langmuir adsorption model and two kinetic models were applied to obtain the related thermodynamic and kinetic data, including the adsorption equilibrium constant (Kads) of (5.9 ± 1.5) × 104 M−1 and adsorption free energy (ΔG) of −21.6 ± 0.6 kJ mol−1. Meanwhile, this method was shown to be able to isolate the elementary processes of adsorption and desorption under steady-state conditions, and gave an adsorption rate constant (ka) and desorption rate constant (kd) of 2089 ± 6.96 M min−1 and 0.35 ± 0.0012 min−1 for a 15 rpm flow rate. The surface interaction process was revealed and the adsorption mechanism proposed by a molecular orientation adsorption model with three-stage-concentration, indicating that CV first adsorbed on Si–O− sites through electrostatic attraction, then on Si–OH sites through hydrogen bonding, and lastly on the surface through van der Waals forces with different CV concentrations. This study can provide a molecular-level interpretation of CV adsorption and provides important insights into how CV adsorption can be controlled at the silica–water interface.
研究领域:
分析化学
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表面科学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
BIOSENSORS & BIOELECTRONICS
·
2021
·
IF 10.618
Shuting Li,Liye Zhu,Longjiao Zhu,Xiaohong Mei,Wentao Xu
Exosomes are regarded as a promising biomarker for the noninvasive diagnosis and treatment of diseases. The value of exosomes for medical research has promoted the search for a fast, efficient, and sensitive detection method. This study reported a sandwich-based evanescent wave fluorescent biosensor (S-EWFB) for exosome detection. A two-step strategy was implemented to take advantages of the simple binding of fluorescent probes with exosomes via the hydrophobic interaction between the cholesteryl and phospholipid bilayer membrane , as well as real-time detection on an evanescent wave liquid-solid interface based on CD63 aptamer-specific capture to form an exosome@fluorescence probe/aptamer sandwich structure. The one-to-many connection between exosomes and signal molecules and the aptamer-modified evanescent wave optical fiber detection platform reduced the detection limit of exosomes to 7.66 particles/mL, with a linear range of 47.5–4.75 × 10 6 particles/mL. The entire detection process was simple, rapid, and real-time and lasted about 1 h while requiring no separation and purification . Additionally, this platform showed excellent surface regeneration capability and exhibited good performance during the analysis of tumor and non-tumor-derived exosomes.
研究领域:
生物传感
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生物医学工程
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纳米技术
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分子生物学
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癌症研究
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Pan Tao,Kaixin Ge,Xing Dai,Danni Xue,Yang Luo,Shixun Dai,Tiefeng Xu,Tao Jiang,Peiqing Zhang
Surface-enhanced Raman scattering (SERS) has great potential in the field of rapid detection of pesticide residues in food. In this paper, a fiber optic SERS sensor excited by evanescent waves was proposed for efficient detection of thiram. Silver nanocubes (Ag NCs) were prepared as SERS active substrates, which had much stronger electromagnetic field intensity than nanospheres under laser excitation due to much more “hot spots”. By using the method of electrostatic adsorption and laser induction, Ag NCs were uniformly assembled at the fiber taper waist (FTW) for enhancing the Raman signal. Different from the traditional way of stimulation, evanescent wave excitation greatly increased the interaction area between the excitation and analyte, while reducing the damage of the excited light to the metal nanostructures. The methods proposed in this work have been successfully used to detect the pesticide residues of thiram and showed good detection performance. The detection limits for 4-Mercaptobenzoic acid (4-MBA) and thiram were determined to be 10–9 and 10–8 M, the corresponding enhancement factor could be 1.64 × 105 and 6.38 × 104. Low concentration of thiram was detected in the peels of tomatoes and cucumbers, indicating its feasibility in actual sample detection. The combination of evanescent waves and SERS provides a new direction for the application of SERS sensors, which had great application potential in the field of pesticide residue detection.
研究领域:
光学传感
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纳米技术
·
分析化学
·
食品安全
✓ 已验证
产品关联
DOI
PubMed
高影响因子
IEEE SENSORS JOURNAL
·
2024
·
IF 4.3
Tingkuo Chen,Haiming Jiang,Kang Xie,Hongyan Xia
This study aims to develop an advanced glucose sensor based on Single-mode fiber - No-core fiber -Single-mode fiber (SMF-NCF-SMF) microfibers modified with glucose oxidase (GOD) for accurate and simultaneous measurement of glucose concentration and temperature, which could significantly enhance diagnostic capabilities in medical and biological applications. The sensor utilizes the evanescent wave principle to detect glucose concentration and the thermal optical effect to measure temperature. Experimental results demonstrate a concentration sensitivity of 2.07 nm/(mg/mL) within the range of 0-3 mg/mL and a temperature sensitivity of -0.35 nm/°C within the range of 25-50°C. These findings highlight the distinct impacts of concentration and temperature on the interference wavelength. By establishing a demodulation matrix, the sensitivities for both concentration and temperature can be separately determined. In-situ temperature monitoring not only eliminates temperature interference but also ensures that GOD remains at its optimal temperature for maximum activity, thereby enhancing the sensitivity and accuracy of glucose concentration detection. Given its high sensitivity, accuracy, and simplicity, this sensor shows promising potential for widespread use in disease diagnosis and biological detection, paving the way for more advanced diagnostic technologies.
研究领域:
生物医学工程
·
光学传感
·
医疗诊断
·
生物技术
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2018
·
IF 6.042
Lili Liang,Long Jin,Yang Ran,Li-Peng Sun,Bai-Ou Guan
Highly sensitive detection of molecular tumor markers is essential for biomarker-based cancer diagnostics. In this work, we showcase the implementation of fiber light-coupled optofluidic waveguide (FLOW) immunosensor for the detection of p53 protein, a typical tumor marker. The FLOW consists of a liquid-core capillary and an accompanying optical fiber, which allows evanescent interaction between light and microfluidic sample. Molecular binding at internal surface of the capillary induces a response in wavelength shift of the transmission spectrum in the optical fiber. To enable highly sensitive molecular detection, the evanescent-wave interaction has been strengthened by enlarging shape factor R via fine geometry control. The proposed FLOW immunosensor works with flowing microfluid, which increases the surface molecular coverage and improves the detection limit. As a result, the FLOW immunosensor presents a log–linear response to the tumor protein at concentrations ranging from 10 fg/mL up to 10 ng/mL. In addition, the nonspecifically adsorbed molecules can be effectively removed by the fluid at an optimal flow rate, which benefits the accuracy of the measurement. Tested in serum samples, the FLOW successfully maintains its sensitivity and specificity on p53 protein, making it suitable for diagnostics applications.
研究领域:
生物医学工程
·
癌症诊断
·
光学传感
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）